Defining 'successful' episodic memory ageing: Implications of methodological heterogeneity

Area of Science:

• Neuroscience
• Gerontology
• Cognitive Psychology

Background:

• Episodic memory declines with age, but some older adults exhibit preserved or enhanced function, termed 'superagers'.
• Existing research on superagers faces challenges due to inconsistent definitions regarding age, memory performance benchmarks, and cognitive assessment tools.
• This heterogeneity complicates the interpretation of cognitive and neural mechanisms underlying exceptional memory in aging.

Purpose of the Study:

• To conduct a scoping review of studies defining 'superagers'.
• To investigate sources of variability in superager definitions across age, episodic memory, and other cognitive criteria.
• To propose a framework for comparing studies and identifying research gaps in superageing.

Main Methods:

• Systematic literature search of MEDLINE and Scopus databases.
• Identification and selection of 78 eligible studies based on predefined criteria.
• Analysis of variability in definition domains: age, episodic memory, and other cognitive factors.

Main Results:

• Significant heterogeneity exists in defining superagers across studies.
• Variations in age criteria, episodic memory benchmarks, and cognitive inclusion/exclusion significantly alter the characteristics of the 'superager' group.
• The composition of the superager cohort is sensitive to the specific definition employed.

Conclusions:

• The definition of superageing significantly influences research outcomes and interpretations of cognitive and neural mechanisms.
• A standardized conceptual framework is needed to enhance cross-study comparability and accelerate insights into the superageing phenotype.
• Understanding definitional variations is crucial for advancing the study of healthy episodic memory ageing and cognitive resilience.